EP1513714A1

EP1513714A1 - Method and device for automatically releasing the automatic parking brake when starting

Info

Publication number: EP1513714A1
Application number: EP03760757A
Authority: EP
Inventors: Philippe Deprez; Emmanuel Devaud; Philippe Planchon; Thomas Spoormans
Original assignee: Renault SAS
Current assignee: Renault SAS
Priority date: 2002-06-20
Filing date: 2003-06-20
Publication date: 2005-03-16
Anticipated expiration: 2023-06-20
Also published as: EP1513714B1; FR2841199B1; US20060049691A1; ES2356907T3; DE60336131D1; ATE499253T1; JP4515256B2; US7665808B2; FR2841199A1; WO2004000622A1; JP2005529795A

Abstract

A method and a device for automatically releasing an automatic parking brake at start-up. A transmitted torque estimation threshold value is determined that enables the vehicle movement to be balanced. Then, at start-up a loop for calculating the transmitted torque estimation is carried out so long as the calculated value does not exceed the threshold value. When the threshold is exceeded, an automatic parking brake-release command is produced.

Description

"Device and method for automatically releasing the automatic parking brake at start-up"

The present invention relates to a method and a device for automatically releasing the automatic parking brake on starting.

In the state of the art, it has already been proposed to produce electric parking brakes which replace the manual parking brakes.

The electric parking brake is associated with a computer which, depending on various vehicle operating signals, enables it to be released automatically without direct intervention by the driver.

In the prior art, a hill start assist system has also been proposed, using the automatic parking brake, and which is based on the detection, in particular, of the deg re of the depressing of the pedal of the clutch to deduce the engine torque available to the wheel on the one hand, and on the other hand for the driver to take off from the vehicle while the latter is maintained on the slope by the actuation of the parking brake automatic.

^• The above system works properly. However, the inventors have found that the solution has a certain cost which should be reduced. They realized that removing the clutch pedal position sensor is one way to reduce this cost. In the same vein, in the previously developed solution, the use of the information of the position of the clutch pedal must be transformed into a value of torque transmitted to the wheel, which notably complicates the means of calculation of the automatic parking brake release controller when the latter works in hill start assistance.

To remedy these drawbacks of the state of the art, the present invention relates to a method assistance in starting a vehicle comprising a powertrain and an Automatic Parking Brake equipped with means for executing an order to release or deactivate the parking brake. The method of the invention consists in performing, at least after a start-up phase of the powertrain:

• A step of estimating a transmitted torque value which balances the vehicle on the slope;

• A loop consisting in executing an incremental calculation of an estimate of the torque actually transmitted at the given time as long as the estimate of the torque actually transmitted is insufficient to exceed the estimate of torque transmitted; then

• A step of producing a release order ^'or disabling the Automatic Parking Brake. According to one aspect of the method, the step of estimating a value of transmitted torque which balances the vehicle on the slope comprises a step for calculating a static model of the vehicle on the slope from a measurement of an angle d inclination delivered by a slope sensor and the knowledge of a determined value representative of the transmission ratio.

According to one aspect of the method, the measurement of an angle of inclination being less than a given threshold, the estimation of a value of transmitted torque which balances the vehicle on the slope is increased by a determined value. According to one aspect of the method, the determined value of increase in the estimate of a value of transmitted torque which balances the vehicle on the slope depends on the measurement of the angle of inclination.

According to one aspect of the method, the incremental calculation step comprises:

a step of reading an effective mean torque value associated with the dynamic state of the powertrain;

- a step of reading an engine speed value; J

- a step of calculating the time derivative of the motor reg;

a step of determining the moment of inertia of the powertrain and of calculating the resistive torque in the form of a product of the moment of inertia of the powertrain by the time derivative of the engine speed;

a step of determining an estimate of torque transmitted according to a relation of the form: ECT = Cme - Jmot x dWm dt According to one aspect of the method, there is provided a step of re-synchronization of the reading of a torque value efficient means and an engine speed value so that each pair of values (Cme, Wm) corresponds to the same time interval. According to one aspect of the method, it is planned to add a predetermined delay, preferably equal to three periods of shift to Top Dead Center of the engine of the powertrain, on the resynchronization value of the estimated average torque value to take into account in particular the waiting time for filling the collector and executing the ignition.

According to one aspect of the method, the re-synchronization step consists in applying the re-synchronization to the derivative value D_Wm of the motor control Wm between two samples separated by a re-synchronization duration in particular according to the relationship: D_Wm = [Wm (8) -Wm (1)] / duration, in which "d urea" determines the re-synchronization period and Wm (1) and Wm (8) the values for the start and end of the re-synchronization period.

According to one aspect of the method, the transmitted torque estimation step (ECT) comprises the comparison of a transmitted torque estimation value (ECT) with a predetermined threshold value (ECT threshold) so that if the threshold is passed a test of an incremented counter at each step estimate of transmitted torque (ECT) in relation to a predetermined threshold (Smin_loop_Delay), so that if the threshold on the counter is exceeded an order to release the Automatic Parking Brake is generated. According to one aspect of the method, the step of estimating the transmitted ECT torque also comprises a predetermined shift step so as to reduce the disruptive effect of the starting and stopping of certain secondary consumers (Consumers) of energy or power supplied by the heat engine, by performing the operation:

ECT_Corr_k = ECT_k + g (Consumers) so that the range in which the motor can be considered at rest is determined and the range during which an offset g (Consumers) on the estimate of transmitted torque can be achieved. According to the invention, four criteria or tests are carried out simultaneously in order to achieve such a shift.

According to one aspect of the method, the shift is carried out at the end of a test during which four conditions are combined:

Wm <Smax_Wm_idle

ABS (D_Wm) <Smax_D_M_idle

THETA_Acc <Smax_acc_idle

D_Acc <0. Conditions under which:

Smax_Wm_id! E represents a threshold value below which the engine speed indicates that the engine is in idle state or idle speed;

Smax_D_M_idle represents a threshold value below which the absolute value ABS (D_Wm) of the time derivative of the engine speed D_Wm indicates that the engine is in idle state or idle speed;

Smax_acc_idle represents a threshold value below which the degree of depressing the accelerator pedal THETA_Acc indicates that the engine is in quiescent or idling speed;

D_Acc represents the time derivative of the degree of depression TH ETA_Acc of the accelerator pedal which is negative when the driver raises the foot of the accelerator pedal; so that if the test is negative, the control returns to the initialization of a CPTR counter, the powertrain being deemed not connected to the drive wheels. ; and so that if the test is positive, the control passes to a test in which it is checked whether the counter CPTR is less than a predetermined threshold value CPTR_seuil; so that if the test is positive, the control goes to a step during which an offset value, initially zero when the CPTR counter is itself initialized in the step, is increased by the value of l ECT estimate in progress; then, the counter value CPTR being incremented by one step during a step and the control returns to the test step; so that if the test is negative, the offset value is transmitted to a routine for calculating an offset value of the estimate of torque transmitted ECT, offset value noted "offset_ECT" which is equal to the ratio of the value " offset ”calculated during the step with the CPTR value of the counter which is, at that time, CPTR_seuil.

According to one aspect of the method, a step is performed to produce information on the driver's activity so that the release of the automatic parking brake is refused in the event of the accelerator pedal being raised.

According to one aspect of the method, a step is carried out to detect a start request while the power train is not engaged.

According to one aspect of the method, the step consists, without using a clutch pedal depression sensor, in detecting the engaged state using two maps of the estimate of torque transmitted as a function of the degree of pedal depression of accelerator respectively established when the wheels are engaged or when the wheels are not engaged or by comparing the value of the estimation of torque transmitted to each of the ad mapping values ressées by measuring the degree of depression of ^'the pedal accelerator for, if the comparison to the first mapping is positive to produce information characteristic of a disengaged state and if the comparison to the second mapping is positive to produce information characteristic of a engaged state. According to one aspect of the method, the step consists, using an all-or-nothing clutch pedal depression sensor, in producing information characteristic of a engaged or disengaged state.

According to one aspect of the method, a step for detecting the no-load speed consists in:

- compare the estimated engine torque information Cme with two idle speed estimation functions in positive rotation fp () and in negative rotation fn ();

- to apply to the function fp () a gain G_Cme_PV at no load applied to the estimated motor torque Cme, an offset

Offset_Cme_PV on the value of engine torque estimated in idle position, and the current value Cme to produce a value of idle speed in positive rotation a priori;

- to apply to the function fn () a gain G_Cme_NV at no load applied to the estimated motor torque Cme, an offset

Offset_Cme_NV on the value of engine torque estimated in idle position, and the current value Cme to produce a value of idle speed in negative rotation a priori;

- compare the value of the engine speed (Wm) to determine whether you are in a positive or negative vacuum regime;

- to authorize the release of the Automatic Parking Brake only if no idle speed is detected.

According to one aspect of the method, a step of detecting saturation of the high-speed heat engine is carried out. so that the release of the Automatic Parking brake in saturation mode is prohibited.

According to one aspect of the process, a step to produce a “flat” start-up service without threshold on the pressing of the accelerator pedal consists of:

- produce an order to release the parking brake on the sole determination that the estimate of torque transmitted ECT is greater than the predetermined threshold ECT Threshold and, in particular without testing a threshold on pressing the accelerator pedal;

- initialize a state variable when starting the vehicle to indicate that the accelerator pedal has not yet been depressed, the variable being represented by Acc_Was_NonZero = 0; - to read a variable representative of the engine idle state (Rest);

- to process the variable Acc_Was_NonZero so that it remains at "1" as soon as the accelerator has been pressed and until the variable Rest returns to "1"; and then consists in authorizing the start "flat" when the variable Acc_Was_NonZero is worth "0" and in testing that the estimate of torque transmitted ECT is greater than a threshold value ECTSeuil to authorize the release of the Automatic Parking Brake and thus ensure take-off of the vehicle by retaining it over a certain acceleration range.

According to one aspect of the method, the “flat” start-up service is extended to a downhill start-up service, first gear engaged.

According to one aspect of the process, the "flat" start-up service is extended to a downhill start-up service, reverse gear engaged.

According to one aspect of the method, a step of detecting an excess of pitching and a step to prohibit the release of the Automatic Parking Brake in a starting situation if the vehicle pitch applied for example by excessive movement of vehicle passengers exceeds a certain predetermined threshold.

According to one aspect of the method, a step for determining a term of anticipation on the release order of the automatic parking brake as a function of predetermined anticipation values which consists, during the elaboration of the release order of the Automatic Parking brake, also execute a step to measure the degree of depressing the accelerator pedal Teta_Acc, then measure a time derivative of the sig nal Teta_Acc of degree of depressing, ie D_Acc, and compare this instantaneous value D_Acc derivative with a predetermined threshold Seuil__Anticipe, so that if the speed of variation of the degree of depression D_Acc is greater than a value Seuil_Anticipe, the loop of incrementation of the estimate value of torque transmitted ECT is interrupted before q ue the test is true and to produce in advance the release order of the Automatic Parking Brake.

The invention also relates to a device for assisting in hill start of a vehicle comprising a power train and an automatic parking brake equipped with a means for executing a release or deactivation order of the parking brake. The device of the invention essentially comprises a computer for a loosening order connected to a sensor of the degree of slope in which the vehicle is engaged and to a sensor delivering information on the speed or speed of rotation of the powertrain of the vehicle .

The invention is characterized by the fact that the computer comprises means for estimating the transmitted torque connected to a first input of a comparison means, a second input of which is connected to means for producing a threshold value of transmitted torque corresponding to the maintenance of the vehicle, so that an output terminal of said means of comparison produces a release order for the electric parking brake according to the method of the invention.

Other characteristics and advantages of the invention will be better understood using the description and appended figures which are:

- Figure 1: a block diagram representing a device according to the invention;

- Figure 2: a flowchart showing the main steps of the method of the invention; - Figures 3 to 5: diagrams explaining an embodiment for preparing the calculation of an estimate of the transmitted torque;

- Figures 6 and 7: means for developing an order to release the electric parking brake; - Figures 8 and 9: a means for processing the estimate of the transmitted torque generated according to the teaching of the invention;

- Figure 10: a means for detecting an abandonment of hill start attempt by the driver;

- Figure 1 1: a means for taking into account the behavior of various drivers on a given vehicle;

- Figure 12: a means for detecting a speed of the vacuum drive motor;

- Figure 13 a means for detecting the saturation of the regime. In Figure 1, there is shown a hill start assist device in an embodiment according to the invention. The vehicle on which the device and the electric parking brake is installed comprises a bus 1 on which signals come from the rest of the vehicle 2, a powertrain control computer 3 and a braking control computer 4, for example of the ABS ™ type. Bus 1 is a CAN ™ standard bus, in an exemplary embodiment. The drive train consists of a heat engine coupled to the drive wheels by a transmission device comprising a gearbox and a clutch which can be controlled by an automatic system and / or by the driver. In other embodiments, the powertrain may include one or more electric machines with or without a heat engine.

The hill start assist device cooperates with a computer 5 for controlling the Automatic Parking Brake 6 which is also connected to bus 1. The control computer 5 is equipped, as is known with a means for producing an automatic parking brake application order, with means for producing an automatic parking brake release order, said application orders or release being generated on a connection line 1 1 to the Automatic Parking Brake proper. If necessary, the control computer 5 is also equipped with means for returning to the bus 1 of the vehicle status information of the automatic parking brake.

The computer 5 for controlling the automatic parking brake is connected by a suitable line with a slope sensor 7. In other embodiments, information on the degree of slope being available on the bus 1, the sensor 7 is replaced. by an equivalent means which takes this information from the data flow passing over the bus 1.

The Automatic Parking Brake used in the invention mainly comprises an electric motor 7 which is controlled by an electric motor controller 8, the electric power supply of which is connected to the on-board network of the vehicle 9 and to the electric ground 10, and whose control parameters (current, voltage, or speed and torque) are transmitted by the control line 1 1 coupled to the computer 5 for controlling the Automatic Parking Brake.

The electric motor 7 cooperates, as is known, with a suitable reducer (not shown) which drives a mechanism 12 shown diagrammatically in FIG. 1 under the form of a bar mounted on the motor shaft 1 3, and the ends of which carry cables respectively 14 and 1 5 which are connected at their ends respectively to a brake control member 16 for a straight wheel and to a member brake control 17 for a left wheel.

When the computer 5 for controlling the automatic parking brake produces a tightening order, an order to activate the electric motor 7 is transmitted by line 11 to the controller 8 which rotates the electric motor 7 so that that the lever 12 tightens the cables 14 and 1 5 with a determined clamping force.

The movable parts 1 8 and 19 of the brakes 16 and 17 come to tighten the discs 20 and 21 so that the Automatic Parking Brake is applied. When the parking brake control computer 5

Automatiq ue produces on the line 1 1 an order to release the Automatic Parking Brake, the rotation of the electric motor 7 is driven in the other direction and the moving parts 18 and 1 9 of the brakes 16 and 17 are released. Using the device of the invention, when the vehicle is stopped in a ramp, the slope sensor 7 delivers a signal representative of the degree of slope in which the vehicle is stopped.

Furthermore, in a hill start situation, the vehicle powertrain produces a torque which is or is not transmitted to the wheels according to whether the clutch is active or not and according to a fraction which depends on the clutch position.

As will be seen below, the principle of the invention consists in determining a condition for the release of the Automatic Parking Brake so that the computer 5 for controlling the Automatic Parking Brake, as a function of the slope measured by the sensor 7 and depending on the engine speed presented on bus 1, produces an order to release the Automatic Parking Brake so that the slope effect is balanced by the engine torque, the vehicle may be in a take-off situation as soon as the threshold is exceeded.

In Figure 2, there is shown a flowchart representative of the main steps of the assistance method during hill start according to the invention.

In a step 30, a step of starting the powertrain is carried out, then in particular when the vehicle is stationary, automatic parking brake in the applied state, a step of initialization of the parking brake control computer 5. Automatic.

The control then goes to a step 31 of determining an estimate of the transmitted torque which corresponds to the threshold from which the Automatic Parking Brake can be released without the vehicle undergoing a backward movement. Control then passes to a step 32 at the heart of which an estimate of the transmitted torque is calculated from the start time, on the one hand, and an offset or increase in transmitted torque which makes it possible to balance the estimate of the transmitted threshold torque which results from both the acceleration action and the clutch action in the case of a conventional vehicle with clutch and accelerator pedal, or by equivalent means in the other types of vehicles.

To this end, the control passes to a test 33 where the new estimate value of the transmitted torque calculated during step 32 is compared with the threshold value established during step 31. If the test is positive, during a step 34, the computer 5 for controlling the automatic parking brake is programmed to produce a release order. If the test is negative, the calculation of a new estimated transmitted torque value is executed during step 32 and the test begins again in a loop.

We will now detail step 31 of calculating a threshold value on the estimate of transmitted torque. This threshold value is defined on the basis of a static model of the vehicle as well as on the idea that the transmission ratio applied by the transmission inserted between the wheels and the powertrain is placed on a determined value of transmission ratio, like a first gear R1 of gearbox with stages ratios. In other embodiments, the hill start assist device cooperates with a means of detecting the transmission ratio, and particularly for a transmission with stepped ratios, a means of detecting the position of the gear lever, for detect if the vehicle is in reverse gear or in other transmission ratios, which makes it possible to increase the sensitivity of the assistance device according to the detection of the driver's intention, if the 'we want to perform start-ups in other reports than the first report. By designating by g_ the transmission ratio, R the radius of the wheel, α the slope in which the vehicle is located, M the mass of the vehicle and g the gravitational constant, the threshold value of the estimate of transmitted torque is defined by a product of terms of the form: ECTseuii = M * g * if n (cc) * p

The threshold value thus calculated indicates the torque which it is necessary to apply to the wheel so as to keep the vehicle in balance on the slope. It is clear that from this threshold value, any increase in the transmitted torque would allow the vehicle to take off. It is therefore possible from this threshold value to produce a release command of the parking brake.

The method and the device for assisting in hill start of the invention thus make it possible, by estimating the transmitted torque, to cause the vehicle to perform hill start without any intervention by the driver on the parking brake paddle, one hand and without the efficie cringe at the ^'start it, on the other. In one embodiment, it has been observed that when the slope sensor produces a very low value of degree of slope α, that is to say when the slope is very small, the assistance device finds a threshold value of the transmission torque estimate ECT _seU ii very close to 0, and the vehicle can then, when the brake is released, set in motion in a parasitic manner.

To avoid this situation, an increase value f is added which depends on the slope values detected and which, when the slopes are low, makes it possible to increase the threshold value of the estimate of transmitted torque. In this embodiment, the computer 5 includes means for determining whether the deg re of slope is less than a given value and, to the positive response of this determination, for adding to the determination of the means already described the threshold value of the estimate of transmitted torque ECT _se uii, a term determined according to the degree of slope α, that is f (α). In one embodiment, the module for calculating the threshold value of the estimate of transmitted torque therefore further comprises a mapping memory, which comprises a plurality of addresses, one for each discrete value produced by a sensor. of suitable slope, and each address containing a digital value representative of the additional value to be added to the torque threshold transmitted when the degree of slope α is low, and a module adding the said additional value read from the mapping memory with the value previously calculated from static data representative of the vehicle statics on the slope and to produce a value corrected for the estimate of the threshold of balance transmitted torque. In a particular mode of realization, the term f (α) is also going to be limited outside the slight slopes to add driving pleasure and / or safety. Its effect is then to hold the vehicle a little more during takeoff. To carry out step 32 of the method of the invention, the computer 5 for controlling the Automatic Parking Brake comprises:

• a first module of readin re torque effective Cme which is supplied by the computer of the ^engine 3 in the form of information circulating on the bus 1 of the vehicle,

A second module for reading the instantaneous speed Wm of rotation of the thermal engine which is supplied by the engine computer 3 in the form of information circulating on the bus 1 of the vehicle,

• a third module making it possible to calculate the time derivative dWm of the speed of rotation at the output of the powertrain from the data of the speed of rotation or engine speed sampled by the second module; • a fourth module for calculating the product of a value of the moment of inertia Jmot characteristic of the engine inertia ^'as well as the output value of said third module;

• a fifth module for subtracting the output value of the fourth module, presented to a subtraction input of the fifth module, from the output value of said first module so that at its output is presented an instantaneous value of the estimate of instantaneous transmitted torque produced according to

a relation: ECT = Cme - J word x dt

In Figure 3, there is shown an explanatory diagram of a cause of error on the estimation of the transmitted torque and on the engine speed.

In the upper part of FIG. 3, there is shown a timing diagram 40 representing successive frames 41 and 42 corresponding to periods referenced #T and # T + 1. At the end of each of these frames, a set of transmitted data is available on the various receivers. . In each frame, the member data is structured according to a protocol recorded by a protocol controller circuit on the CAN bus, in digital words representative of parameter values transmitted on the bus and inserted with various phases and periodicities.

Thus, in the example illustrated in FIG. 3, during frame 41 of the period #T, a first word Cmeγ of a first transmitted variable and a second word Wm _T of a second transmitted variable will both be available at the end of frame #T. However, because of periods T1 and T2 for the first and second words transmitted which are different and / or greater than the period of the frame, or even because the latter varies, only the first word Cmeτ + ι is available at the end of the frame # T + 1. The second word provided in frame T + 1 is received in a subsequent frame 43

In the invention, it is necessary that the computer 3 for controlling the powertrain (see FIG. 2) produce:

> an estimated value of the estimated average torque, written in the form of a digital word Cme on the CAN bus; and> a value of the engine speed recorded in the form of another digital word Wm on the CAN bus. Due to the production mechanisms of each of these two values, and due to the occupations of the transmission frame according to the CAN bus protocol, it follows that, at a determined date t, the FPA Automatic Parking Brake control computer. 5 to execute an order re 1 1 to release the Automatic Parking Brake in a hill start situation, does not receive at the same time the two data corresponding to the same date and necessary, which • prevents a proper estimate from being made.

To remedy this problem, the invention provides a means for correcting the values Cme of the estimated average torque and Wm of the engine speed as well as resetting the information available depending on the data rate according to the frames transmitted on CAN bus 1.

In FIG. 4, a means of calculating the estimate of the transmitted torque 50 transmits an instantaneous value of the estimated average torque Cme to a module 51 for writing on the CAN bus 1 so that, at determined times, an instantaneous value the estimated average torque is available on CAN bus 1.

Furthermore, a module 52 for calculating the estimation of the engine speed Wm is connected to an input of the writing module 51 on the CAN bus 1 so that, at determined times, a value for estimating or measuring the speed motor is available on CAN bus 1.

To this end, information relating to a particular state of the heat engine, such as the top dead center instant t _PH , is supplied to suitable inputs of the modules 50 and 52 so as to synchronize the calculations of the first word Cme and of the second word

Wm.

A controller 53 for exchanges on the CAN bus 1 receives from modules 50 and 52 information according to which new data is available, the write module 51 being connected to controller 53 to warn it of a write operation on the CAN bus 1 and a controller output of the controller 53 being connected to a write authorization input on the CAN bus 1 of the module 51. The module 51 for writing to the CAN bus 1 thus generates a data frame as a function of the multiple data which it injects on the CAN bus.

The heat engine shown in reference 54 is coupled to a top dead center sensor 55 to generate, at its output 56, information t _{PM H} of the top dead center of the instant when the latter appears.

A reading module 57 on the CAN bus is arranged for receiving a reading order via a connection 58 to the controller 53 CAN bus and acknowledges on line 59 the end of the reading of a frame.

An output 60 of the reading module 57 makes it possible to transmit respectively to a register 61 the successive values of estimation of the estimated engine torque decoded on the frames received by the module 67 and to a register 62 the successive values of engine speed Wm decoded on the frames received by the module 67.

The CAN bus controller circuit 53 includes control outputs, respectively a control output 63 connected to a read authorization input of the engine speed register 62 and a control output 64 connected to a read authorization input of the register 61 of the estimates of the transmitted torque, so that the outputs respectively 65 of the register 61 and 66 of the register 62 are connected to the suitable inputs of a re-synchronization circuit 67 which allows at each instant to maintain a value corrected as a function the indication of the point instant _. dead high tp _M H supplied by the output 56 of the sensor 55, values respectively 68 instantaneous of the estimated average torque and 69 of engine speed.

The re-synchronization circuit 67 comprises a memory which contains a table on a cycle of data pairs so that the sequence number of a value representative of a first word received on its first input is associated with a number d order of a value representative of the sequence number of a second word received. The re-synchronization circuit 68 also includes registers of sequences of successive values of the first word and or of the second word and means, for, as a function of the associations of sequence numbers of the aforementioned memory for applying a couple of outputs d 'a first word and a second word corresponding to a single instant of calculation. The pair of re-synchronized words is then presented at outputs 68 and 69.

In Figure 5, there is shown an embodiment of a re-synchronization circuit 67 which essentially works on the engine speed and which makes it possible to exploit a shift in the mechanism for providing pairs of words (Cme, Wm) which corresponds to a characteristic effect during the acceleration of the heat engine, a situation which always appears when the vehicle is maintained on the slope ^' with the Automatic Parking Brake applied.

To the input terminal 65 of the module 67 of, synchronization of the data on the CAN bus 1, there was connected the write input of a synchronization register 70 of the estimate of transmitted torque.

To this end, a sequencer 71 receives by a suitable input the signal indicative of top dead center 56 and transmits write orders on a line 72 and read on a line 73 to terminals for writing and reading the register 70. In the case of a read signal, the signal corresponds to the engine speed with an offset of a period proportional to the engine speed. This measurement makes it possible to make the refresh time of the information on the engine speed dependent on the value of the engine speed itself. At a time of re-synchronization predetermined with respect to the availability indicated on line 72, the line 73 for reading transmits the value maintained in register 70 to a register 74. The register 74 permanently presents at its output 68 an available value estimation of the synchronized transmitted torque.

The input terminal 56 of the re-synchronization module 67 is connected to the input of a stack 76 of registers in which a plurality of successive values of the engine speed Wm acquired at successive instants on the CAN bus is maintained. 1. To this end, a sequencer 71 has two write and read command outputs respectively 77 and 78 which make it possible to maintain the plurality of values by placing the most up-to-date value on the first address marked "1" in the stack. 76 and pushing down the values contained in the following registers of stack 76.

A subtractor circuit 79 comprises:

a positive input connected to a reading output of the battery 76 on which the oldest value of the engine speed Wm maintained in the battery 76 is available, and

- a negative input to which is connected the most recent value of the engine speed available also on the input terminal 66 of the module 67. An input 80 of the subtractor circuit 79 receives a value representative "duration" of the duration elapsed during the acquisition between the oldest value, such as the eighth value "8", denoted Wm (1) and received in a particular embodiment, and the most recent value "1" denoted Wm (8) so that 'at the output 81 of the subtractor circuit 79 is available a value representative of an estimated value corrected by the engine speed: D_Wm = [Wm (8) -Wm (1)] / duration.

The calculated value available at the output of circuit 79 is loaded into a register 82 so that at its output 83 is available a value of the time derivative of the synchronized engine speed D_Wm _S ync.

The reading and writing of the registers 74 and 82 are carried out under the control of the sequencer 71 which has respectively a write command line 84 and a write command line 85.

The writing command is carried out under the command of the sequencer 71 which is managed by a register 86 in which is recorded a time offset value or delay ΔT which corresponds to a desired delay in transmission of the synchronized values to the rest of the estimator of so that we can take into account in particular:

- the filling time of the engine collector, and - the ignition delay when the heat engine is in the acceleration phase, as is the case when starting on a hill.

In an exemplary embodiment, the inventors have found a best effect when a delay ΔT equivalent to three successive Top Dead Points was applied before starting the synchronization and the transfer of the couples of the first Cme and second Wm or D_Wm words of values sy ^{'nchronisées.}

In Figure 6, there is shown a particular embodiment of the method of the invention. The method of the invention consists in, during a start phase S0, re-synchronize the data concerning the engine speed and the estimated average torque, in calculating the threshold value of the estimate of the transmitted torque according to what has was described using the flowchart of Figure 2, then to execute the repetition of the test that the estimate of the transmitted torque calculated on the given date, is above the threshold ECTseuϋ for at least a predetermined number of samples Smin_Loop_delay .

To this end, the counter CPTR is set to an initial value 0 during a step S1, then the control passes to a standby test S2 of a value ECT_k representative of the estimation calculation of the transmitted torque.

When this value is available, the control passes to a step S3 of incrementing the counter CPTR and then to a test S4 of the estimate of transmitted torque ECT_k relative to the threshold C I threshold -

If the test is negative, the control returns to the initialization of the counter CPTR = 0 of step S1.

If the test S4 is positive, the control passes to a test S5 where it is checked whether the counter CPTR has reached its maximum value Smin_Loop_delay.

If the test is positive, the control goes to a step S6 during which the parking brake control computer 5 Automatic FPA gives an order to release the parking brake 7.

If the test S5 is negative, the control returns to the input of the test S2 awaiting the arrival of the next sample for estimating the transmitted torque ECT_k.

In FIG. 7, there is shown an embodiment of a means of calculating the computer 5 implementing the flow diagram of FIG. 6. This means of calculating the computer 5 comprises a counter 90 which maintains a numerical value CPTR and the updates each event presented at its entry marked "+" by increasing it by a predetermined value as "1". The CPTR value of counter 90 is. then available on a read output terminal.

The calculating means of the computer 5 includes an input 91 on which the value ECT_k is loaded and which is connected, on the one hand, to the input of a circuit 93. for detecting the arrival of a value ECT_k and to a first input of a comparator 92.

The detection output of the module 93 for detecting the arrival of a sample ECT_k is connected to the input “+” for increment control of the counter 90, the read output terminal of which is connected to a first input of a comparator 93.

An ECT threshold value, maintained in a register

94 is transmitted to a second input of the comparator 92. The comparator 92 has a first output 96 and a second output 95, complementary to each other, so that if the test carried out by the comparator 92 is positive, the first output 96 goes to the active state and is connected to a first input of an AND gate 97, while the second output 95 goes to the inactive state and is connected to a reset input terminal at an initial value like the value '0' of the counter 90.

The count value CPTR available in the counter 90 is transmitted to a first input of a second comparator 98, a second input of which is connected to a register 99 now the maximum count value at the end of which the release authorization can be executed.

For this purpose, when the test carried out by the second comparator

98 is positive, its output switches to the active state and is connected ^'to a second input of the AND gate 97 so that the output 1 00 of the AND gate 97 switches to the active state for indicating a release of the authorization Automatic parking brake.

In a particular embodiment, the value Smin_Lop_Delay loaded in register 99 is determined as a function of the sampling period or loop rate of the algorithm of FIG. 6 and of the delay or delay desired between the first overrun by the value of estimated transmitted torque ECT of the threshold value ECT _seU ii and the implementation of the release order of the parking brake FPA. According to the invention, the register 99 includes a means for writing a value thus determined of Smin_Lop_Delay which is activated during the initialization of the vehicle or during its manufacture or during its maintenance using a production tool known to those skilled in the art, or else when a type of conductor is detected using the on-board computer 1 which transmits on the bus 1 a characteristic value of Smin_Lop_Delay associated with the conductor detected at l using for example the starting key or the type of driver according to an algorithm for detecting the type of driving carried out by the driver. In another particular embodiment not shown in the drawings, the estimate value of transmitted ECT torque received at terminal 91 of the module in FIG. 7 also receives a predetermined offset so as to reduce the disruptive effect of the setting walking and stopping of certain secondary consumers _ι energy or power supplied by the heat engine. Such a shift is made upstream of the detection circuit 91 and of the input of the comparator 92, using an adder which performs the operation:

ECT__Corr_k = ECT_k + g (Consumers) The method of the invention provides a means for determining the range in which the motor can be considered to be at rest and the range during which an offset g (Consumers) on the estimate of transmitted torque can be achieved. According to the invention, four criteria or tests are carried out simultaneously to achieve such a shift.

In FIG. 8, an organogram of the method of the invention has been represented. The offset calculation entry point 101 makes it possible to place, during a step 102, a particular counter CPTR at an initial value such as the value 0. Then, the control passes to the test step 103 during which four conditions are combined:

Wm <Smax_Wm_idle ABS (D_Wm) <Smax_D_M_idle TH ETA_Acc <Smax_acc_idle

D_Acc == 0.

Conditions under which: Smax_Wm_idle represents a threshold value below which the engine speed indicates that the engine is in idle state or idle speed;

Smax_D_M_idle represents a threshold value below which the absolute value ABS (D_Wm) of the time derivative of the engine speed D_Wm indicates that the engine is in idle state or idle speed; Smax_acc_id le represents a threshold value below which the degree of depression of the THETA_Acc accelerator pedal indicates that the engine is in the idle state or idle speed;

D_Acc represents the time derivative of the degree of depressing THETA_Acc of the accelerator pedal which is negative when the driver takes his foot off the accelerator pedal.

If the test 103 is negative, the control returns to the initialization 102 of the counter CPTR. The drive train is deemed not connected to the drive wheels. If the test 103 is positive, the control passes to a test 104 where it is checked whether the counter CPTR is lower than a predetermined threshold value CPTR_seuil.

If the test 104 is positive, the control goes to a step 105 during which an offset value, initially zero when the counter CPTR is itself initialized in step 1 02, is increased by the value of the estimate

ECT in progress.

Then, the counter value CPTR is incremented by one step during a step 106 and the control returns to the test step 103.

If the test 104 is negative, the offset value is transmitted to a routine 107 for calculating an offset value of the estimate of torque transmitted ECT, offset value noted “offset_ECT” which is equal to the ratio of the value “offset Calculated in step 1 05 with the CPTR value of. counter which is, at that time, CPTR_seuil.

In FIG. 9, there is shown an embodiment of a device implementing the method of the flow diagram of FIG. 8.

The circuit of FIG. 9 has three input registers respectively:

- register 1 10 of the value Wm of instantaneous engine speed,

- the register 1 1 1 of degree of depressing of the accelerator pedal in a variable THETA_acc,

- the register 1 12 which maintains the instantaneous estimate value of the torque transmitted ECT.

Register 1 10 includes a read output respectively connected to a first input of a comparator 1 1 3, a second input of which is connected to a register 1 14 which maintains an upper threshold value Smax_Wm_idle representative of the takeoff limit reg.

The register 110 is also transmitted _, an input from a circuit 1 15 for calculating the derivative D Wm of the speed of rotation or of the engine speed W_m of which an output on which the absolute value of the time derivative of the engine speed is maintained is connected to a first input of a comparator 1 16 of which a second input is connected to the read output of a register 1 17 in which is maintained the threshold value of variation or time derivative of the engine speed Smax_D_Wm_idle of takeoff of the vehicle.

The register 1 1 1 which maintains the depressing angle or the pressing of the accelerator pedal THETA_acc is connected to a first input of a comparator 1 18 of which a second input is connected to the reading output of a register 1 19 in which a threshold value Smax_acc_idle is recorded corresponding to a maximum degree of depressing of the accelerator pedal in the situation of take-off of the vehicle. The value THETA_acc is also transmitted to a circuit 120 for calculating the time derivative of the depressing of the accelerator pedal D_acc, an output of which is transmitted to a first input of a comparator 121.

A second input of comparator 121 is connected to the read output of a register 122 in which a threshold value of the acceleration drift is maintained as a zero or substantially zero value so as to detect a situation in which the conductor maintains the depressing of the accelerator pedal in a stable position. The outputs of the four comparators 1 16, 1 13, 1 18, 121 are connected to the corresponding inputs of an AND gate 124 whose output is connected to an increment input of a counter 129 whose output count value 130 is connected respectively to a first input of a comparator 131 and to an input terminal of a buffer circuit 132. The second input of comparator 131 is connected to the read output of a register 133 in which is recorded a maximum count value for the CPTR counter. The output of the counter 131 is connected to a control terminal 134 of the buffer circuit 132 so that an output terminal 135 of the buffer 132 copies the value presented at its input 130 when the control terminal 134 is in the high state, and passes it to a denominator input of a divisor arithmetic circuit 136.

The register 12 which maintains the instantaneous value for estimating the transmitted torque ECT is supplied to a first input of an adder 137, a second input of which is connected to the reading output of a register 138 maintaining a partial value of accumulated sum .

A write input 139 of the register 138. is connected to the instantaneous output 140 of the adder 137 so that, at each instant, the register 138 contains a summed value of the successive estimated values of transmitted torque ECT_k during the positive evolution of the counter CPTR 129.

The output 140 of the adder 137 is also connected to a numerator input of the divider arithmetic circuit 136 so that, when the output signal 134 of the comparator r goes high, the value accumulated by the adder 137 is divided by the value of the counter 129 and so that this accumulated value is output at a register 141 maintaining an estimate value of torque transmitted with offset according to the principle of the algorithm of FIG. 8. In FIG. 10, another circuit has been shown implementing an arrangement of the invention making it possible, using the information provided by the sensor for depressing the accelerator pedal, to produce information concerning the activity of the driver. In one embodiment, the circuit for measuring the activity of the driver of the invention makes it possible to refuse the release of the parking brake in the event of the accelerator pedal being raised. In such a situation, it can be considered that the raising the accelerator pedal indicates that the driver's attempt to start has been abandoned.

In another embodiment, filtering of a too strong ascent of the accelerator pedal is added, considering that the detection of a temporal derivative of the depressing angle of the accelerator pedal is a measure a first engine start action.

To this end, the device of the invention comprises a register 1 50 in which the instantaneous value of time derivative D_Acc of the degree of depressing THETA_Acc of the accelerator pedal produced using the circuit 120 mentioned above in the figure is kept. 9.

The read value of register 150 is transmitted to the first inputs of two comparators, respectively 151 and 152, the second inputs of which are respectively connected to read outputs of registers 153 and 154. Register 153 maintains a lower threshold value Smin_D_Acc_TakeOff, characteristic of an upper limit on the accelerator pedal depressing speed. If the time derivative D_Acc is lower than the recorded value, the comparator 151 produces an active value at its output which is transmitted to a first input of an AND gate 1 55. Similarly, if this time derivative D_Acc is smaller or also at a lower threshold value Smax_D_Acc_TakeOff, recorded in register 154, the comparator circuit 152 goes to the active state and places its output connected to the second input of the AND gate 1 55 to the active value.

The output of the AND gate 155 is connected to a first input of a second AND gate 156, a second input of which is connected to the output terminal 100 of the circuit of FIG. 7. Authorization to release the Automatic Parking Brake is then presented at the output 1 57 of the circuit of fig ure 10 if the output of the AND gate 155 is active at the same time as the output terminal 1 02. The invention also provides a way to detect a hill with the engine start request is not engaged, and yet without the presence depression degree sensor of the clutch pedal or ^• the state 'clutch.

To this end, according to the invention, two maps 163 and 164 respectively representing the degree of depression of the accelerator pedal and the estimate of transmitted torque are carried out during the initialization of the computer. The bases of these two maps make it possible to establish whether the engine is disengaged from the drive wheels or whether the heat engine is mechanically connected to the drive wheels.

To this end, several maps can be loaded depending in particular on the type of driver entered in a driver identification register, or depending on the type of vehicle when the circuit of the invention is intended to equip different vehicles with a range from the same manufacturer.

The circuit of the embodiment of fig ure 1 1 essentially comprises two access registers respectively: - a register 160 to maintain the instantaneous value of the depressing degree of the accelerator pedal THETA_Acc, and a register 161 to maintain the instantaneous value for estimating a torque transmitted ECT.

Furthermore, a module 162 for detecting the identification of the driver and / or of the vehicle makes it possible to determine which cartography to use when executing the method of the invention. The circuit or module 162 for detecting the identification of the driver and / or of the vehicle comprises a command output line which is connected to command inputs 165 and 166 respectively of a first mapping memory 1 63 and of a second mapping memory 164. The first mapping memory 163 comprises a list of threshold values on the degree of depressing of the accelerator pedal which makes it possible to distinguish whether the driver is in the clutch phase or not ; this threshold value being determined by the detection of the driver and / or vehicle type of the module 162.

The second mapping memory 164 contains a threshold value from which the vehicle can be considered to be engaged on the estimate of transmitted torque CT. To this end, the registers 160 and 161 are connected to first inputs of a first comparator 167 and of a second comparator 168, the second inputs of which are respectively connected to outputs 1 69 of the first mapping memory 163 and 170 of the second mapping memory 164. The outputs of the two comparators 167 and 168 are connected to inputs of an AND gate 171, the output of which is connected 172 to a loosening order.

The loosening order 172 can be combined with the loosening order coming from the output 157 of the circuit of FIG. 10 and / or from the output 100 of the circuit of FIG. 7.

In part B of FIG. 11, the diagrams of the evolution of the estimate of the torque transmitted ECT on the ordinate are shown as a function of the thrust angle THETA_Acc of the accelerator. The estimate of transmitted torque is substantially constant at a very low value according to the direction of rotation of the engine according to a curve C1 when the powertrain is empty, that is to say when the clutch is not activated. The curve for the evolution of the estimate of transmitted ECT torque is represented by the line C1, and more generally it is a range of values which does not depend on the angle of penetration of the accelerator by a few Newton . meters.

In a second type of curve such as curve C2, from a threshold S0 for depressing the accelerator pedal, the estimate of transmitted torque increases very rapidly. Thus, it is possible to determine a threshold S1 from which one can begin to test the estimate of transmitted torque and a threshold S2 of transmitted torque above which one can be sure that the heat engine is engaged on the drive wheels. of the vehicle. These values S1 and S2 are recorded respectively in the first mapping memory 163 and the second mapping memory 164 as a function of the type of vehicle or of type of driver or of his identification for a given vehicle.

In Figure 12, there is shown a means for detecting the idle speed when the vehicle is running unladen.

The principle of this part of the invention consists in using the information of estimated engine torque Cme, and in carrying out an integration of the information in order to estimate the speed of the powertrain and to determine whether it is running at no load. The estimated idle speed Wm_0 can then be compared to the actual engine speed Wm and if it remains lower than the idle speed Wm_0, it is deduced therefrom that the vehicle is not unladen and we can then authorize a loosening.

In one _embodiment. the circuit of FIG. 12 includes an input register 180 in which the value Cme of the estimated engine torque produced on the engine computer is maintained. The value of estimated engine torque 180 is transmitted to the first inputs of two modules, respectively 181 and 182, in which two functions, respectively fp () of estimated idle speed in rotation are executed, with an estimated engine torque CME positive and fn () for estimation of idle speed in rotation with a negative estimated CME engine torque. The module 181 makes it possible to estimate a value of no-load speed as a function of the estimated engine torque Cme presented at the terminal or register 180 and as a function of a couple of parameters estimated in advance by successive tests of no-load accelerations on a sample of vehicles corresponding to the type of vehicle on which the device of the invention is mounted. In a first register 183, a gain is applied to the estimated engine torque Cme, ie the value G_Cme_PV when empty. In a second register 184, an offset is recorded on the value of engine torque estimated in idle position, ie Offset_Cme_PV. The function fp () recorded in the calculation module 1 81 uses the three arguments Cme of register 180, G_Cme_PV of register 183 and Offset_Cme_PV of register 184.

At the output terminal 185 of 181 computing ^module to the function fp () is present an estimated value of reg vacuum ime

W_vide_p equal to a determined value of the function fp () applied to the three input arguments 180, 183 and 184 according to the relation:

W_vide_p = fp (G_Cme_PV, Offset_Cme_PV, Cme). In a particular embodiment, the function fp () is defined by the relation:

W_vide_p = G_Cme_PV x Cme + Offset_Cme_PV.

The module 182 makes it possible to estimate a value of no-load speed as a function of the estimated engine torque Cme presented at the terminal or register 1 80 and as a function of a couple of parameters estimated in advance by successive no-load acceleration tests on a sample of vehicles corresponding to the type of vehicle on which the device of the invention is mounted. In a first register 186, a gain is applied to the estimated engine torque Cme, that is to say the value G_Cme_NV when empty. In a second register 187, an offset is recorded on the value of the engine torque estimated in idle position, ie Offset_Cme_NV. The function fn () recorded in the calculation module 181 uses the three arguments Cme from register 180, G_Cme_NV from register 186 and Offset_Cme_NV from register 187.

At the output terminal 188 of the module 182 for calculating the function fn () is present an estimated value of no-load speed

W_vide_n equal to a determined value of the function fn () applied to the three input arguments 180, 186 and 187 according to the relation:

W_vide_n = fn (G_Cme_NV, Offset_Cme_NV, Cme).

In a particular embodiment, the function fn () is defined by the relation:

W_vide n = G Cme NV x Cme + Offset_Cme NV. not a word

The circuit of FIG. 12 then comprises a register 189 in which the instantaneous value of the engine speed Wm is maintained and which is supplied to first inputs, respectively of a first comparator 190 and of a second comparator 191, including the second inputs are respectively connected to the output 185 of the modu le 181 and to the output 188 of the module 1 82. The comparators 190 and 191 switch and go to the active state when the engine speed is lower than the estimated values of W_vide_ n or W_vide_p according to the type of running regime on the vehicle's engine. The outputs of comparators 190 and 191 are connected to first AND gate inputs 192 and 193, the second inputs of which are respectively connected to the reading output of a register 194 in which an active value for release of the automatic parking brake is maintained. of the invention. The outputs of the AND gates 192, 93 are connected to the inputs of an OR gate 195 and the output of which is placed on an output register which maintains a loosening value in detection of idle state.

In Figure 13, there is shown an embodiment of a circuit for performing a step of the method of the invention. During the development of the invention, the inventors recognized that the injection system which equips the thermal engine of the powertrain could at high speeds, that is to say when the engine rotation speed is high, be cut suddenly. However, the module which is associated with the powertrain and which transmits on the bus 1 the value Cme of estimated average torque which is used on the computer of the invention to develop the loosening order becomes erroneous. In this situation, the method of the invention consists in replacing the value representative of the estimated average torque Cme of the heat engine with a particular correction value in saturation regime.

To this end, the circuit of FIG. 13 includes an input terminal Wmot which receives a value representative of the speed and a register 200 now a threshold value Smax_Wm_saturation beyond which the shutdown of the injection system can occur.

The two aforementioned values are transmitted to the input terminals of a comparator 201 whose output is connected to the input 204 of a switching circuit 203 of which a first input terminal 205 receives a value representative of the estimated average torque Cme from the computer associated with the powertrain and a second input terminal of which is connected to an estimated average torque value corrected when the engine is saturated. When the comparator output terminal

201 goes to active state because the engine speed has exceeded the preset threshold of register 200, the correction value of register

202 is presented at the output 206 of the switching circuit 203 rather than the value Cme.

The method of the invention may also include additional options. In particular, the method of the invention finds application in the situation of a flat start, the vehicle being stationary on horizontal ground. Such a service can be implemented using the device of the invention when configuring the vehicle for production, maintenance or when detecting the type of driver or the driver when the latter takes place in the vehicle.

The “horizontal” character of the terrain is defined by a test to determine whether the signal representative of the measurement of the slope angle is, in absolute value, less than a threshold of angle of inclination or slope noted Smin_Slope_NonZero, said threshold being recorded in a slope angle threshold register, and said signal being produced by the slope sensor 7 (FIG. 1). In this service, the method of the invention consists in producing an order to release the parking brake on the sole determination that the estimate of torque transmitted ECT is greater than the predetermined threshold ECT Threshold and, in particular without testing a threshold on the support of the accelerator pedal like this is imposed in the hill start as described above.

To this end, the method of the invention consists in initializing a state variable when starting the vehicle to indicate that the accelerator pedal has not yet been depressed, the variable being represented by Acc_Was_NonZero = 0.

In the remainder of the execution of the method of the invention, if the "flat" starting service is implemented, a variable representative of the engine idle state, variable represented by Rest, is in the False state ( "0") when at least one of the four conditions already described below is not true: Wm <Smax_Wm_idle ABS (D_Wm) ≤ Smax_D_M_idle THETA_Acc ≤ Smax_acc_idle D_Acc ≤ 0.

And which then returns to the True state ("1") when the four conditions are satisfied.

According to the method of the invention, the variable

Acc_Was_NonZero remains "1" as soon as the accelerator ^'and was supported until the Rest variable returns to "1". The method of the invention then consists in authorizing the flat start ”when the variable Acc_Was_NonZero is equal to“ 0 ”.

It is then enough to test that the estimate of torque transmitted

ECT is greater than an ECTS threshold value to authorize the release of the Automatic Parking Brake and thus ensure take-off of the vehicle by retaining it over a certain acceleration range.

The circuit of the device of the invention which implements the “flat” starting service essentially comprises: - a circuit for activating the flat starting service during the configuration of the vehicle for production, for maintenance or during the detection of the type of driver or the driver when the latter takes place in the vehicle producing a logic signal at "0" if the service is not implemented and at "1" if the service is implemented; .

a “flat” situation detection circuit for detecting that the signal representative of the angle of inclination produced by the slope angle sensor 7 is in absolute value less than a threshold value recorded in a suitable register and representative of the “flat” situation limit;

- a first AND gate to combine the circuit output signals to activate the flat start service and the "flat" situation detection circuit;

- a circuit for developing the variable Acc_Was_NonZero which includes a comparator of the deg re of depressing the accelerator pedal to a very low predefined threshold for depressing and a reset circuit as soon as the variable Rest from the rest of the device of starting the invention returns to "0";

a circuit for testing the value of the estimate of transmitted ECT torque from the rest of the starting device of the invention at a threshold value ECTSeuil and for producing an order to release the Automatic Parking Brake;

- a second AND gate to combine the "flat" release order from the circuit to test the value of ^ estimate of torque transmitted ECT at the output of. the first AND gate, the output of which is connected to the electric motor brake controller of the Automatic Parking Brake.

The release service on the flat without accelerator offers an improvement in the comfort of the take-off service of the parked vehicle. Without acceleration, takeoff is slower, comfort is improved. In a first variant, the “flat” starting service is extended to the case of starting downhill, first gear engaged. To this end, the "flat" start service is also activated when a negative slope is detected and the first gear is engaged.

To this end, the device of the invention comprises: - a circuit for activating the start-up service "downhill, first gear engaged" during the configuration of the vehicle for production, maintenance or upon detection of the type of driver or the driver when the latter takes place in the vehicle which produces a logic signal at "0" if the service is not implemented and at "1" if the service is implemented;

a situation detection circuit "downhill, first gear engaged" to detect that the signal representative of the angle of inclination produced by the slope angle sensor 7 is less than a negative threshold value recorded in a suitable register representative of the situation limit "downhill, first gear engaged";

- a third AND gate to combine the circuit output signals to activate the start-up service "downhill, first gear engaged" and the situation detection circuit "downhill, first gear engaged";

a fourth AND gate to combine the output of the third AND gate and the circuit output to test the value of the estimate of transmitted ECT torque from the rest of the starting device of the invention at a threshold value ECTSeuil and for produce an order to release the Automatic Parking Brake from a "downhill, first gear engaged" situation.

In a second variant, the "flat" starting service is extended to the case of starting downhill in "reverse".

To this end, the "flat" start service is also activated when a positive slope is detected and the reverse gear is engaged. To this end, the device of the invention comprises:

- a circuit to activate the starting service "downhill, reverse gear engaged" when configuring the vehicle for production, maintenance or when detecting the type of driver or the driver when the latter takes place in the vehicle which produces a logic signal at "0" if the service is not implemented and at ^" " 1 "if the service is implemented;

a situation detection circuit "downhill, reverse gear engaged" to detect that the signal representative of the angle of inclination produced by the slope angle sensor 7 is greater than a positive threshold value recorded in a suitable register representative of the situation limit "downhill, reverse gear engaged";

- a third AND gate to combine the circuit output signals to activate the start-up service "downhill, reverse gear engaged" and the situation detection circuit "downhill, reverse gear engaged";

a fourth AND gate to combine the output of the third AND gate and the circuit output to test the value of the estimate of transmitted ECT torque from the rest of the starting device of the invention at a threshold value ECTSeuil and for issue a parking brake release order

Automatic situation "downhill, reverse gear engaged".

In another embodiment, the vehicle being provided with a sensor for measuring the depression of the clutch pedal in all or nothing, the signal from this sensor being at ^"1" when the clutch is open the “empty” situation of the vehicle is thus directly detected without the need to test the various situations in which the powertrain has been separated from the drive wheels. In another embodiment, the method of the invention also includes a step of detecting an excess of pitching. In a first application, the pitching sensor makes it possible to detect that, while the vehicle is accelerating, the brakes are still applied and therefore to confirm an order to release the automatic parking brake in a later step. In a second application, the step of detecting a pitch value is followed by a step to prohibit the release of the Automatic Parking Brake in a starting situation if the <pitch of the vehicle applied for example by too much movement of the vehicle passengers exceeds a certain predetermined threshold.

To this end, the device of the invention comprises a circuit for detecting an excess of pitching whose output is active if the excess of pitching exceeds a predetermined threshold in a register. The output of the circuit for detecting an excess of pitching is combined by a first inverting input of an AND gate, another input of which is connected to the output of the device described above on which the release order of the Automatic Parking Brake is located. , and the exit from the AND gate producing the release order of the Automatic Parking Brake outside of an excessive pitching.

The circuit for detecting an excess of pitch comprises an input terminal which receives a signal produced by the slope angle sensor 7 which has a resolution sufficient to detect an excess of pitch. The tilt angle detection signal is transmitted to the input of a circuit to produce a signal representative of the time derivative of the tilt angle detection signal, the output of which is connected to a input of a comparator, the other input of which is connected to a register maintaining a threshold pitch excess value. The comparator output is active when the derivative of the signal representative of the angle of inclination of the sensor 7 is greater than the predetermined threshold. The excess pitch threshold value is, in one embodiment produced by a generator of excess pitch threshold values as a function of the angle of inclination produced by the sensor 7. In another embodiment , the generator of excess pitch threshold values comprises a first series of single values in a first starting direction and a second series of single values in a second starting direction. The method of the invention also makes it possible to provide a service for anticipating the dynamics of start-up. To this end, the method of the invention also includes a step for determining an anticipation term on the release order of the Automatic Parking Brake as a function of predetermined anticipation values.

To this end, the method of the invention consists, during the execution of the method for drawing up the release order of the Automatic Parking Brake already described, also performing a step of measuring the degree of depressing of the pedal. of accelerator Teta_Acc, then to measure a, time derivative of the signal Teta_Acc of degree of depression, that is to say D_Acc, and to compare this instantaneous value of derivative D_Acc with a predetermined threshold Seui! _Anticipate, so that if the speed of variation of degree of depression D_Acc is greater than a Seuil_Anticipe value, the increment loop of the estimated torque estimate value ECT is interrupted before test 33 (Figure 2) is true and to produce the release order of the Automatic Parking Brake.

The device for implementing the method of the invention comprises for this purpose a circuit for calculating the time derivative D_Acc of the signal Teta_Acc of degree of depression provided by the slope angle sensor 7 (Fig u re 1). The circuit for calculating the derivative D_Acc has an output which is connected to a first input of a comparator whose other input is connected to a generator with a predetermined value of a Threshold_Anticipate value, so that its output is active if the value Seu il_Anticipe is exceeded. The comparator output signal is then transmitted to a first input of another AND gate, the second input of which is connected to a circuit to detect that the estimate of torque transmitted ECT is being incremented, for example by detecting the evolution of the CPTR counter (83, Figure 6). The output of the other AND gate is then used as an advance release order for the Automatic Parking Brake.

In a particular embodiment, the predetermined threshold Seui! _Anticipe is a predetermined function depending on the degree of slope measured by the slope angle sensor 7 (Figure 1). The implementation device of the invention comprises for this purpose a generator of a predetermined threshold Seuil_Anticipe in the form of a table of threshold values addressed by the value of the degree of slope measured by the slope angle sensor 7. The value Seuil_Anticipe is then transmitted to the aforementioned comparator of the device of the invention.

In one embodiment of the method of the invention, the start-up dynamics anticipation service also includes a step to take into account the response time of the electric motor fitted to the Automatic Parking Brake as well as the different games in the braking mechanism it activates.

In the method of the invention, provision is made for anticipating the starting of the parking brake in order to take into account the dynamics of the driver and the response time of the electromechanical system. The response time of the electromechanical system is known by prior measurements, if necessary with a calibration procedure. Let Tr be this response time. At each instant, the torque estimate transmitted ECT and its time derivatives, such as (d / dt), are determined. ECT. These time derivatives make it possible to take into account account the dynamism of the driver, the value of the first time derivative increasing with the dynamism of the driver According to the invention, a step of prediction by extrapolation is carried out. In one embodiment, an extrapolation or prediction is then made on the prediction value of the estimate of torque transmitted by a relation of the form (at order 1):

ECT_predit (Tr) = ECT + Tr x (d / dt). ECT

An operator to execute a prediction must therefore receive as inputs:

a characteristic value of response time Tr, for example recorded in a suitable memory calibrated if necessary by a response time processor of the automatic parking brake system; - at least one current value of a torque estimate transmitted ECT_encours. The operator then comprises a diverter which comprises in known manner:

a memory of a previous acquisition of an estimate of transmitted torque ECT_ancien and in a particular embodiment a memory of a time coefficient Ta proportional to the time separating two acquisition or estimates of transmitted torque;

- a subtractor to perform the operation ECT_encours - ECT_ancien;

- a divider to carry out the temporal derivation proper by an operation of the form (ECT_encours - ECT_ancien) / Ta.

The operator also includes: - a multiplier, one input of which is connected to the response time memory Tr, and the other input of which is connected to the output of the divider producing the value (d / dt). ECT and whose output produces the value Tr x (d / dt). ECT; - an adder to perform the operation ECT_predit (Tr) = ECT_encours + Tr x (d / dt). ECT.

Anticipation can then, according to the method of the invention, be executed by the execution of a test whose threshold, S_min_predit and / or S_max_predit, is predetermined. Such a test is of the form: S_min_préd it <ECT_prédit <S_max_prédit, so that if the test is positive, an early release order of the automatic parking brake is generated at the output of the computer 5 for controlling the Automatic Parking Brake. The device of the invention for implementing the method of the invention comprises at least:

a memory of a threshold value S_min_predit and / or S_max_predit of anticipation loosening test for storing in a fixed or calibratable manner according to a processor for calibrating the loosening anticipation thresholds;

a comparator of the output value of the aforementioned operator to execute a prediction on the engine torque estimation value at at least one of said threshold values S_min_predit and / or S_max_predit so that a signal d is produced authorization to release the Automatic Parking Brake early if the comparator is activated.

In one embodiment, the device of the invention consists of a processor having a software architecture in four blocks, namely:

- an input data entry block including engine speed Wm, vehicle speed Vv, slope angle, estimated average torque Cme, degree of depressing of the accelerator pedal TETA_Acc, in particular taken on CAN bus 1;

- a signal processing block applied to the input data which operates in particular digital filtering on all or part of the input data and makes corrections to scales or units;

- an initialization parameter block of the inventive method comprising in particular the threshold values and the initialization of ^'counters;

- a process execution block for generating an order to release the Automatic Parking Brake.

Claims

REVEN DICATIONS

1 - Method for assisting the starting of a vehicle comprising a powertrain and an Automatic Parking Brake equipped with a means for executing an order to release or deactivate the Automatic Parking Brake, characterized in that it consists to be executed, at least after a starting phase of the powertrain:

• A step of estimating a transmitted torque value which balances the vehicle on the slope; • A loop consisting in executing an incremental calculation of an estimate of the torque actually transmitted at the given time as long as the estimate of the torque actually transmitted is insufficient to exceed the estimate of torque transmitted; then

• A step of producing an order to release or deactivate the Automatic Parking Brake.

2 - Method according to claim 1, characterized in that the step of estimating a transmitted torque value which balances the vehicle on the slope comprises a step for calculating a static model of the vehicle on the slope from a measurement of an angle of inclination delivered by a slope sensor (7) and of the knowledge of a determined value representative of the transmission ratio.

3 - Method according to claim 2, characterized in that, the measurement of an angle of inclination being less than a given threshold, the estimate of a value of transmitted torque that balances the vehicle on the slope is increased d 'a determined value.

4 - Method according to claim 3, characterized in that q ue the determined value of increasing the estimate of a transmitted torque value which balances the vehicle on the slope depends on the measurement of the angle of inclination.

5 - Method according to claim 1, characterized in that the incremental calculation step (32) comprises: a step of reading an effective mean torque value (Cme) associated with the dynamic state of the powertrain;

- a step of reading an engine speed value (Wm);

- a step of calculating the time derivative of the engine speed;

a step of determining the moment of inertia of the powertrain (Jmot) and of calculating the resistive torque in the form of a product of the moment of inertia of the powertrain by the time derivative of the engine speed;

- a step of determining an estimate of torque transmitted according to a relation of the form: ECT = Cme - Jmot x dWm dt 6 - Method according to claim 5, characterized in that it comprises a step of re-synchronization of the reading an effective mean torque value (Cme) and an engine speed value (Wm) so that each pair of values (Cme, Wm) corresponds to the same time interval. 7 - Method according to claim 6, characterized in that it consists in adding a predetermined delay, preferably equal to three periods of change to Top Dead Center of the engine of the powertrain, on the resynchronization value of the average torque value estimated to take account in particular of the waiting time for filling the collector and the execution of the ignition.

8 - Method according to claim 6 or 7, characterized in that the re-synchronization step consists in applying the re synchronization on the derivative value (D_Wm) of the motor regime r Wm) between two samples separated by a duration of re synchronization in particular according to the relation: D_Wm = [Wm (8) - Wm (1)] / duration, in which "duration" determines the period of re synchronization and Wm (1) and Wm (8) the start and end values of the re-synchronization period.

9 - Method according to one of claims 5 to 8, characterized in that the step of estimating the transmitted torque (ECT) comprises:

- a step (S4) of comparing an estimate value of transmitted torque (ECT) with a predetermined threshold value (ECTseuil);

- if the predetermined threshold value (ECTseuil) is exceeded, a step (S5) of testing the output value of a counter

(S3), incremented during each step of estimation of transmitted torque (ECT), with respect to a predetermined threshold value (Smin_loop_Delay),

- if the predetermined threshold value (Smin_loop_Delay) is exceeded, a step of producing an order to release the Automatic Parking Brake.

10 - A method according to claim 9, characterized in that the step of estimating the transmitted ECT torque further comprises a step for executing a predetermined offset so as to reduce the disruptive effect of starting and / or l 'shutdown of certain secondary consumers (Consumers) of energy or power supplied by the heat engine, by performing the operation:

ECT__Corr_k = ECT_k + g (Consumers) A preliminary step to determine a range in which the motor can be considered at rest and a range during which an offset g (Consumers) on the estimate of transmitted torque that can be executed.

1 1 - Method according to claim 1 0, characterized in that the step for executing an offset is carried out at the end of a test (1 03) during which four conditions are combined: Wm <Smax_Wm_idIe ABS (D_Wm) ≤ Smax_D_M dle THETA Ace <Smax ace idle D_Acc == 0. conditions under which:

Smax_Wm_id le represents a threshold value below which the engine control indicates that the engine is in idle state or idle speed;

Smax_D_M_idle represents a threshold value below which the absolute value ABS (D_Wm) of the time derivative of the engine speed D_Wm indicates that the engine is in idle state or idle speed; Smax_acc_idle represents a threshold value below which the degree of depressing of the accelerator pedal TH ETA_Acc indicates that the engine is in idle state or idle speed; D_Acc represents the time derivative of the degree of depression TH ETA_Acc of the accelerator pedal which is negative when the driver takes his foot off the accelerator pedal; so that if the test (1 03) is negative, the control returns to the initialization (1 02) of a counter (CPTR), the powertrain being deemed not connected to the drive wheels; and so that if the test (103) is positive, the control passes to a test (104) where it is checked whether the counter (CPTR) is less than a predetermined threshold value (CPTR_threshold); so that if the test (104) is positive, control goes to a step (105) during which an offset value, initially zero when the counter (CPTR) is itself initialized in step (1 02), is increased by the value of the current ECT estimate; then, the counter value (CPTR) being incremented by one step during a step (106) and the control returning to the test step (1 03); so that if the test (104) is negative, the offset value is transmitted to a routine (107) for calculating an offset value of the estimate of torque transmitted ECT, offset value noted "Offset_ECT" which is equal to the ratio of the value "offset" calculated during step (105) with the value (CPTR_seuil) of the counter.

12 - Method according to one of the preceding claims, characterized in that it comprises a step for producing information on the activity of the driver so that the release of the automatic parking brake is refused in the event of the pedal being raised. 'accelerator.

13 - Method according to one of the preceding claims, characterized in that it comprises a step for detecting a start request while the powertrain is not engaged.

14 - Method according to claim 13, characterized in that the step consists, without using a clutch pedal depression sensor, in detecting the engaged state using two maps of the torque estimate transmitted as a function of the degree of depression of the accelerator pedal respectively established when the wheels are engaged and when the wheels are not engaged and by comparing, the value of the estimate of torque transmitted to each of the values of maps addressed by measuring the degree of depressing the accelerator pedal so that, if the comparison to the first mapping is positive to produce information characteristic of a disengaged state and if the comparison to the second mapping ie is positive to produce characteristic information of 'a engaged state.

15 - Method according to claim 13, characterized in that the step consists in using a sensor for depressing the clutch pedal in all or nothing to produce information characteristic of a ^' engaged or disengaged state.

16 - Method according to any one of the preceding resells, characterized in that it comprises a step for detecting the no-load regime, which consists in: - comparing the information of estimated engine torque (Cme) with two functions of estimation of idle speed in rotation with an estimate of positive transmitted torque fp () and in rotation with an estimate of negative transmitted torque fn (); - to apply to the function fp () a gain (G_Cme_PV) at no load applied to the estimated engine torque (Cme), an offset (Offset_Cme_PV) on the value of engine torque estimated in idle position, and the current value (Cme ) to produce an idle speed value in rotation with an estimate of positive transmitted torque a priori;

- to apply to the function fn () a gain (G_Cme_NV) at no load applied to the estimated engine torque (Cme), an offset (Offset_Cme__NV) on the value of engine torque estimated in idle position, and the current value (Cme ) to produce a value of no-load speed in rotation with an estimate of negative transmitted torque a priori;

- comparing the value of the engine speed (Wm) to determine whether there is an idle, rotational speed with an estimate of positive transmitted torque or with an estimate of negative transmitted torque;

17 - Method according to one of the preceding claims, characterized in that it comprises a step of detecting saturation of the thermal engine at high speed so that the release of the Automatic Parking brake is prohibited in saturation mode.

18 - Method according to one of the preceding claims, characterized in that it comprises a step for producing a starting service "flat" without threshold on the support of the accelerator pedal which consists:

- to produce an order to release the parking brake on the sole determination that the estimate of torque transmitted ECT is greater than the redefined threshold p ECT Threshold and, particularly without testing a threshold on pressing the accelerator pedal;

- initialize a state variable when starting the vehicle to indicate that the accelerator pedal has not yet been depressed, the variable being represented by Acc_Was_NonZero

= 0;

- to read a variable representative of the engine idle state (Rest);

- to process the variable Acc_Was_NonZero so that it remains at "1" as soon as the accelerator has been pressed and until the variable Rest returns to "1"; and in that it then consists in authorizing the start "flat" when the variable Acc_Was_NonZero is worth "0" and in testing that the estimate of torque transmitted ECT is greater than a threshold value ECTSeuil to authorize the release of the brake Automatic parking and thus ensuring takeoff of the vehicle by retaining it over a certain acceleration range.

19 - The method of claim 18, characterized in that it consists in extending the start service "flat" to a start service downhill, first gear engaged.

20 - The method of claim 18, characterized in that it consists in extending the start service "flat" to a start service downhill, reverse gear engaged.

21 - Method according to one of the preceding claims, characterized in that it comprises a step of detecting an excess of pitching and a step to prohibit the release of the Automatic Parking Brake in starting situation if the pitching of the vehicle applied for example by too much movement of the passengers in the vehicle exceeds a certain predetermined threshold.

22 - Method according to one of the preceding claims, characterized in that it comprises a step for determining an anticipation term on the release order of the automatic parking brake as a function of predetermined anticipation values. which consists, during the elaboration of the release order of the Automatic Parking Brake, to also execute a step of measuring the degree of depression of the accelerator pedal Teta_Acc, then to measure a time derivative of the sig nal Teta_Acc of degree ^" of depression, that is to say D_Acc, and to compare this instantaneous value of derivative D_Acc with a predetermined threshold Seuil_Anticipe, so that if the speed of variation of the degree of depression D_Acc is greater than a value Seuil_Anticipe, the loop d ' increment of the estimated torque value transmitted ECT is interrupted before the test (33; Fig ure 2) is true and to produce in advance the release order of the Automatic Parking Brake.

23 - Device for assisting in hill start of a vehicle comprising a powertrain and an Automatic Parking Brake equipped with means (7, 8) for executing an order to release or deactivate the parking brake by setting implements the method according to at least one of the preceding claims, characterized in that it comprises a computer (5) of a loosening order connected to a sensor (7) of the degree of slope in which the vehicle is engaged and to a sensor delivering information on the speed or speed of rotation of the powertrain of the vehicle and characterized in that the computer (5) comprises a means for estimating the transmitted torque (ECT) connected to a first input of a means comparator, a second input of which is connected to a means for producing a transmitted torque threshold value corresponding to the holding of the vehicle, so that an output terminal of said comparison means pro provides a release order (1 1) for the electric parking brake (7, 8). 24 - Device according to claim 23, characterized in that it comprises:

A first module for reading the effective mean torque Cme which is supplied by a computer (3) of the engine in the form of information circulating on the bus (1) of the vehicle, "• a second module for reading the instantaneous speed Wm of rotation of the thermal engine which is supplied by the engine calculator (3) in the form of information circulating on the bus (1) of the vehicle, • a third module allowing to calculate the time derivative dWm of the speed of rotation at the output of the powertrain from the data of the speed of rotation or engine speed taken by the second module;

• a fourth module for calculating the product of a value of the moment of inertia Jmot characteristic of the inertia of the motor as well as the output value of said third module;

• a fifth module for subtracting the output value of the fourth module, presented to a subtraction input of the fifth module, from the output value of said first module so that at its output is presented an instantaneous value of the estimate of instantaneous transmitted torque produced according to dWïn, a relation: ECT = Cme - Jmot x dt

25 - Device according to one of claims 23 or 24, characterized in that q ue, the values of estimated engine torque (Cme) and engine speed (Wm) being supplied on frames of a bus (1) by a computer motor control (3), it includes a re-synchronization circuit (67).

26 - Device according to claim 25, characterized in that the re-synchronization circuit (67) comprises: - a memory which contains a table on a cycle of data pairs so that the order number is associated d 'a value representative of a first word received on its first entry with a sequence number of a value representative of the sequence number of a second word received, - registers of successive value sequences of the first word and or of the second word and a means for, as a function of the associations of serial numbers of the aforementioned memory, to apply as output a couple of a first word and of a second word corresponding to one and the same instant of calculation and to present the couple of synchronized words ^' re is at output terminals

(68, 69).

27 - Device according to claim 25 or 26, characterized in that the re-synchronization circuit (67) works essentially on the engine speed and makes it possible to exploit a shift in the mechanism for providing pairs of words (Cme, Wm ) a characteristic effect during acceleration of the heat engine and which comprises: a synchronization register (70) of the estimate of transmitted torque (Cme); a sequencer (71) which receives a signal (56) indicative of top dead center and which transmits write (72) and read (73) orders to the register (70); a register (74) of an available value for estimating the synchronized transmitted torque; a stack (76) of registers in which a plurality of successive values of the engine speed (Wm) acquired at successive instants on the CAN bus (1) is maintained; a differentiator circuit (79) which comprises:

- a positive input connected to a reading output of the battery (76) on which is available the oldest value of the engine speed Wm maintained in the battery (76), and ^•

- a negative input to which is connected the most recent value of the motor control also available on the input terminal (66) of the module (67); - An input (80) which receives a representative value "duration" of the time elapsed during the acquisition between the oldest value, and the most recent value so that at the output (81) of the differentiating circuit (79) a value representative of a synchronized value of the derivative is available time-averaged engine speed according to a relation of the form:

D_Wm _sy nc = [Wm (8) -Wm (1)] / duration; loaded into a register (82). 28 - Device according to claim 27, characterized in that a register write control terminal (82) maintaining a synchronized value of the time derivative averaged engine speed is connected to the sequencer (71) that manages a register (86 ) in which a time offset or delay value ΔT is recorded which corresponds to a desired delay in transmitting the synchronized values to the rest of the estimator so that one can take into account in particular:

- the filling time of the engine collector, and

- an ignition delay when the heat engine is in the acceleration phase, as is the case when starting on a hill.

29 - Device according to claim 24, characterized in that it comprises a counter (90) which maintains a numerical value CPTR and updates it with each event presented at its entry noted "+" by increasing it by a value predetermined as "1"; an input (91) on which is loaded the value ECT_k a value being incremented by the estimate of transmitted torque and which is connected, on the one hand, to the input of a circuit (93) for detecting the arrival of a value ECT_k and at a first input of a comparator (92); the detection output of the module (93) for detecting the arrival of a sample ECT_k is connected to the input “+” for increment control of the counter (90), the read output terminal of which is connected to a first input of a comparator

(93); a register (94) containing a threshold value ECTseuil, and transmitted to a second input of the comparator (92); the comparator (92) has a first output (96) and a second output (95), complementary to each other, so that if the test carried out by the comparator (92) is positive, the first output (96 ) goes to the active state and is connected to a first input of an AND gate (97), while the second output (95) goes to the inactive state and is connected to a reset input terminal at a initial value as the value '0' of the counter (90); a second comparator (98) whose first input receives the count value C PTR available in the counter (90) and whose second input is connected to a register (99) maintaining the maximum count value at the end of which l release authorization can be executed; so that, when the test carried out by the second comparator (98) is positive, its output goes to the active state and is connected to a second input of the AND gate (97) so that the output (1 00) of the door AND (9) 7 goes to the active state to indicate an authorization to release the Automatic Parking Brake. 30 - Device according to claim 29, characterized in that it comprises a register (99) containing a value (Smin_Lop_Delay) determined as a function of the sampling period or loop rate and of the delay or delay desired between the first overrun by the estimated transmitted torque value ECT of the threshold value ECT _seU ii and the carrying out of the release order of the parking brake FPA, the register (99) comprising a means of writing a value thus determined of Smin_Lop_De ! ay which is activated during the initialization of the vehicle or either during its manufacture or during its maintenance using a production tool known to those skilled in the art, or else when a type of conductor carried out using the on-board computer 1 which transmits on the bus 1 a characteristic value of Smin_Lop_Delay associated with the detected conductor using for example the starting key or the type of driver according to a driving type detection algorithm performed by the driver.

31 - Device according to claim 30, characterized in that, using an adder which performs the operation: ECT_Corr_k = ECT_k + g (Consumers), the estimate value of the transmitted ECT torque received at the terminal ( 91) also receives a predetermined offset so as to reduce the disruptive effect of starting and stopping certain secondary consumers of energy or power supplied by the heat engine, offset effected upstream of the circuit ( 91) of detection and of the comparator input (92).

32 - Device according to claim 31, characterized in that it comprises a circuit for executing an offset according to the idle speed state or under load. 33 - Device according to one of claims 23 to 32, characterized in that it comprises one. circuit (150 - 172) for detecting the activity of the driver using two comparators (151, 152) of the time derivative (D_Acc) of the degree of depressing of the accelerator pedal at an interval of degree of depression (SMIN_D_Acc_Takeoff,

SMAX_D_Acc_Takeoff) in two registers (1 53, 154) and using an AND gate (156) to confirm the release order of the Automatic Parking Brake.

34 - Device according to one of claims 23 to 33, characterized in that it comprises a circuit (160-172) for detecting the engaged or non-engaged state of the power train using a plurality of maps ( 163, 164) containing a series of values of estimate of transmitted torque (ECT) as a function of the deg re of depressing the accelerator pedal established according to whether the clutch is active or not, using a AND gate (171) to validate the production of the release order of the Automatic Parking Brake depending on the type of driver, the degree of depressing of the accelerator pedal (TETA_Acc) and the estimated torque transmitted (ECT), an AND gate (171) validating the release order of the Automatic Parking Brake.

35 - Device according to one of claims 23 to 34, characterized in that it comprises a circuit (1 80 - 1 95) for detecting the unladen state of the vehicle according to the direction of rotation which comprises two generators (1 81, 182) of a function determining the idle engine speed, connected to two comparators (1 90, 1 91) of the instantaneous value of the engine speed (Wm), and of two AND gates (192, 1 93) to validate an automatic parking brake release order.

36 - Device according to one of claims 23 to 35, characterized in that it comprises a circuit (200 - 206) for determining a state of saturation of the heat engine which comprises a comparator (201) for determining whether the engine speed ( Wm) and to apply or not a corrected value in a correction means (202, 203) of. estimated engine torque values (Cme).

37 - Device according to one of claims 23 to 36, characterized in that it comprises a circuit for implementing a "flat" start-up service which essentially comprises:

- a circuit to activate the flat start service when configuring the vehicle for production, maintenance or when detecting the type of driver or the driver when the latter takes place in the vehicle producing a signal. logical to "0" if the service is not implemented and to

"1" if the service is implemented;

- a “flat” situation detection circuit for detecting that the signal representative of the angle of inclination produced by the slope angle sensor (7) is in absolute value less than a threshold value recorded in a reg ist suitable and representative of the situation limit "flat";

- a first AND gate to combine the circuit output signals to activate the flat start service and the "flat" situation detection circuit; - a circuit for developing the variable Acc_Was_NonZero which includes a comparator of the degree of depressing of the accelerator pedal to a predetermined very low depressing threshold and a reset circuit as soon as the variable Rest from the rest of the device start of the invention returns to "0";

- a second AND gate to combine the "flat" loosening order from the circuit to test the value of the estimate of torque transmitted ECT at the output of the first AND gate and whose output is connected to the electric motor controller Automatic Parking Brake.

38 - Device according to one of claims 23 to 37, characterized in that it comprises a circuit for implementing a starting service in descent, first gear engaged which comprises: - a circuit for activating the starting service "in descent, first gear engaged ”when configuring the vehicle for production, maintenance or when detecting the type of driver or the driver when the latter takes place in the vehicle which produces a logic signal at“ 0 ”if the service is not implemented and at “1” if the service is implemented;

a circuit for detecting a “downhill situation, first gear engaged” to detect that the signal representative of the angle of inclination produced by the slope angle sensor 7 is less than a negative threshold value recorded in a suitable register representative of the situation limit "downhill, first gear engaged";

- a third AND gate to combine the circuit output signals to activate the start-down service, first gear engaged ”and the situation detection circuit“ downhill, first gear engaged ”;

Automatic "downhill, first gear engaged" situation. 39 - Device according to one of claims 23 to 38, characterized in that it comprises a circuit for implementing a starting service in descent in "reverse" which comprises:

- a circuit to activate the starting service "downhill, reverse gear engaged" when configuring the vehicle for production, maintenance or when detecting the type of driver or the driver when the latter takes place in the vehicle which produces a logic signal at "0" if the service is not implemented and at "1" if the service is implemented;

- a fourth AND gate to combine the output of the third AND gate and the circuit output to test the value of the estimate of the transmitted ECT torque from the rest of the starting device of the invention at a threshold value ECTSeuil and to produce an order to release the Automatic Parking Brake from a "downhill, reverse gear engaged" situation.

40 - Device according to one of claims 23 to 39, characterized in that it comprises a circuit for detecting an excess of pitching whose output is active if the excess of pitching exceeds a predetermined threshold in a register, the output of the circuit for detecting an excess of pitching being combined by a first inverting input of an AND gate, another input of which is connected to the output of the device described above on which is the order to release the Automatic Parking Brake, and the exit from the door AND producing the release order of the Automatic Parking Brake outside an excess of pitching.

41 - Device according to claim 40, characterized in that the circuit for detecting an excess of pitch comprises an input terminal which receives a signal produced by the slope angle sensor (7) which has a sufficient resolution to detect a excess pitch, transmitted to the input of a circuit to produce a signal representative of the time derivative of the tilt angle detection signal whose output is connected to an input of a comparator whose other input is connected to a register maintaining an excess pitch threshold value. The comparator output is active when the derivative of the signal representative of the angle of inclination of the sensor 7 is greater than the predetermined threshold.

42 - Device according to claim 41, characterized in that it comprises a generator of excess pitch values of threshold as a function of the angle of inclination produced by the sensor (7) to produce the value of threshold d 'excess pitching.

43 - Device according to claim 42, characterized in that the generator of excess pitch values comprises a first series of threshold values in a first starting direction and a second series of threshold values in a second starting direction.

44 - Device according to one of claims 23 ^' to 43, characterized in that it comprises a circuit for providing a service for anticipating the dynamics of starting which comprises a circuit for calculating the time derivative D_Acc of the signal Teta_Acc of degree of penetration provided by the slope angle sensor (7; Figure 1) connected to a first input of a comparator whose other input is connected to a generator with a predetermined value of a value Threshold_Anticipates, so its output is active if the value is exceeded Seuil_Anticipe whose comparator output signal is then transmitted to ^a first input of another AND gate whose second input is connected to a circuit for detecting that the estimation of the torque transmitted ECT is being incremented, for example by detecting the evolution of the counter CPTR (83; Fig ure 6) and the output of the other door AND is then used as an order to release the Frei n Automatic Parking.

45 - Device according to claim 44, characterized in that it also comprises a generator of a predetermined threshold Seuil_Anticipe in the form of a table of threshold values addressed by the value of the degree of slope measured by the angle sensor slope (7), the value Seuil_Anticipe then being transmitted to the aforementioned comparator.

46 - Device according to one of claims 23 to 46, characterized in that it also comprises a circuit for taking into account the response time of the Automatic Parking Brake and the dynamism of the driver by executing a anticipation or prediction ( ECT_predit) on the estimated torque transmitted (ECT) which includes:

- a prediction operator to execute an operation of the form: ECT_predit (Tr) = ECT + Tr x (d / dt). ECT, in which Tr is a characteristic value of the response time of the electromechanical system and the time derivative ((d / dt). ECT) on the estimate of transmitted torque is an estimate of the dynamism of the driver; - a prediction test operator on the estimated torque transmitted (ECT_predit) to at least one threshold (S__min_predit and / or S_max_predit) of loosening test with predetermined anticipation, recorded and / or calibratable in a memory, so that or produce an early release order of the Automatic Parking Brake if the test operator is activated.

47 - Device according to one of claims 23 to 46, characterized in that it comprises a processor having a software architecture in four blocks: - a block for entering the input data including the engine speed Wm, the speed of the vehicle Vv, the angle of slope, the estimated average torque Cme, the degree of depression of the accelerator pedal TETA_Acc, in particular taken from the CAN bus (1);

- a signal processing block applied to the input data which operates in particular digital filtering on all or part of the input data and performs corrections of scales or units;

a block for initializing the parameters of the method of the invention comprising in particular the threshold values and the initializations of the counters;

- an execution block of the method according to one of claims 1 to 22 for generating an order to release the Automatic Parking Brake.